1 /*
2  * EFI Test Driver for Runtime Services
3  *
4  * Copyright(C) 2012-2016 Canonical Ltd.
5  *
6  * This driver exports EFI runtime services interfaces into userspace, which
7  * allow to use and test UEFI runtime services provided by firmware.
8  *
9  */
10 
11 #include <linux/miscdevice.h>
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/proc_fs.h>
15 #include <linux/efi.h>
16 #include <linux/slab.h>
17 #include <linux/uaccess.h>
18 
19 #include "efi_test.h"
20 
21 MODULE_AUTHOR("Ivan Hu <ivan.hu@canonical.com>");
22 MODULE_DESCRIPTION("EFI Test Driver");
23 MODULE_LICENSE("GPL");
24 
25 /*
26  * Count the bytes in 'str', including the terminating NULL.
27  *
28  * Note this function returns the number of *bytes*, not the number of
29  * ucs2 characters.
30  */
31 static inline size_t user_ucs2_strsize(efi_char16_t  __user *str)
32 {
33 	efi_char16_t *s = str, c;
34 	size_t len;
35 
36 	if (!str)
37 		return 0;
38 
39 	/* Include terminating NULL */
40 	len = sizeof(efi_char16_t);
41 
42 	if (get_user(c, s++)) {
43 		/* Can't read userspace memory for size */
44 		return 0;
45 	}
46 
47 	while (c != 0) {
48 		if (get_user(c, s++)) {
49 			/* Can't read userspace memory for size */
50 			return 0;
51 		}
52 		len += sizeof(efi_char16_t);
53 	}
54 	return len;
55 }
56 
57 /*
58  * Allocate a buffer and copy a ucs2 string from user space into it.
59  */
60 static inline int
61 copy_ucs2_from_user_len(efi_char16_t **dst, efi_char16_t __user *src,
62 			size_t len)
63 {
64 	efi_char16_t *buf;
65 
66 	if (!src) {
67 		*dst = NULL;
68 		return 0;
69 	}
70 
71 	if (!access_ok(VERIFY_READ, src, 1))
72 		return -EFAULT;
73 
74 	buf = memdup_user(src, len);
75 	if (IS_ERR(buf)) {
76 		*dst = NULL;
77 		return PTR_ERR(buf);
78 	}
79 	*dst = buf;
80 
81 	return 0;
82 }
83 
84 /*
85  * Count the bytes in 'str', including the terminating NULL.
86  *
87  * Just a wrap for user_ucs2_strsize
88  */
89 static inline int
90 get_ucs2_strsize_from_user(efi_char16_t __user *src, size_t *len)
91 {
92 	if (!access_ok(VERIFY_READ, src, 1))
93 		return -EFAULT;
94 
95 	*len = user_ucs2_strsize(src);
96 	if (*len == 0)
97 		return -EFAULT;
98 
99 	return 0;
100 }
101 
102 /*
103  * Calculate the required buffer allocation size and copy a ucs2 string
104  * from user space into it.
105  *
106  * This function differs from copy_ucs2_from_user_len() because it
107  * calculates the size of the buffer to allocate by taking the length of
108  * the string 'src'.
109  *
110  * If a non-zero value is returned, the caller MUST NOT access 'dst'.
111  *
112  * It is the caller's responsibility to free 'dst'.
113  */
114 static inline int
115 copy_ucs2_from_user(efi_char16_t **dst, efi_char16_t __user *src)
116 {
117 	size_t len;
118 
119 	if (!access_ok(VERIFY_READ, src, 1))
120 		return -EFAULT;
121 
122 	len = user_ucs2_strsize(src);
123 	if (len == 0)
124 		return -EFAULT;
125 	return copy_ucs2_from_user_len(dst, src, len);
126 }
127 
128 /*
129  * Copy a ucs2 string to a user buffer.
130  *
131  * This function is a simple wrapper around copy_to_user() that does
132  * nothing if 'src' is NULL, which is useful for reducing the amount of
133  * NULL checking the caller has to do.
134  *
135  * 'len' specifies the number of bytes to copy.
136  */
137 static inline int
138 copy_ucs2_to_user_len(efi_char16_t __user *dst, efi_char16_t *src, size_t len)
139 {
140 	if (!src)
141 		return 0;
142 
143 	if (!access_ok(VERIFY_WRITE, dst, 1))
144 		return -EFAULT;
145 
146 	return copy_to_user(dst, src, len);
147 }
148 
149 static long efi_runtime_get_variable(unsigned long arg)
150 {
151 	struct efi_getvariable __user *getvariable_user;
152 	struct efi_getvariable getvariable;
153 	unsigned long datasize = 0, prev_datasize, *dz;
154 	efi_guid_t vendor_guid, *vd = NULL;
155 	efi_status_t status;
156 	efi_char16_t *name = NULL;
157 	u32 attr, *at;
158 	void *data = NULL;
159 	int rv = 0;
160 
161 	getvariable_user = (struct efi_getvariable __user *)arg;
162 
163 	if (copy_from_user(&getvariable, getvariable_user,
164 			   sizeof(getvariable)))
165 		return -EFAULT;
166 	if (getvariable.data_size &&
167 	    get_user(datasize, getvariable.data_size))
168 		return -EFAULT;
169 	if (getvariable.vendor_guid) {
170 		if (copy_from_user(&vendor_guid, getvariable.vendor_guid,
171 					sizeof(vendor_guid)))
172 			return -EFAULT;
173 		vd = &vendor_guid;
174 	}
175 
176 	if (getvariable.variable_name) {
177 		rv = copy_ucs2_from_user(&name, getvariable.variable_name);
178 		if (rv)
179 			return rv;
180 	}
181 
182 	at = getvariable.attributes ? &attr : NULL;
183 	dz = getvariable.data_size ? &datasize : NULL;
184 
185 	if (getvariable.data_size && getvariable.data) {
186 		data = kmalloc(datasize, GFP_KERNEL);
187 		if (!data) {
188 			kfree(name);
189 			return -ENOMEM;
190 		}
191 	}
192 
193 	prev_datasize = datasize;
194 	status = efi.get_variable(name, vd, at, dz, data);
195 	kfree(name);
196 
197 	if (put_user(status, getvariable.status)) {
198 		rv = -EFAULT;
199 		goto out;
200 	}
201 
202 	if (status != EFI_SUCCESS) {
203 		if (status == EFI_BUFFER_TOO_SMALL) {
204 			if (dz && put_user(datasize, getvariable.data_size)) {
205 				rv = -EFAULT;
206 				goto out;
207 			}
208 		}
209 		rv = -EINVAL;
210 		goto out;
211 	}
212 
213 	if (prev_datasize < datasize) {
214 		rv = -EINVAL;
215 		goto out;
216 	}
217 
218 	if (data) {
219 		if (copy_to_user(getvariable.data, data, datasize)) {
220 			rv = -EFAULT;
221 			goto out;
222 		}
223 	}
224 
225 	if (at && put_user(attr, getvariable.attributes)) {
226 		rv = -EFAULT;
227 		goto out;
228 	}
229 
230 	if (dz && put_user(datasize, getvariable.data_size))
231 		rv = -EFAULT;
232 
233 out:
234 	kfree(data);
235 	return rv;
236 
237 }
238 
239 static long efi_runtime_set_variable(unsigned long arg)
240 {
241 	struct efi_setvariable __user *setvariable_user;
242 	struct efi_setvariable setvariable;
243 	efi_guid_t vendor_guid;
244 	efi_status_t status;
245 	efi_char16_t *name = NULL;
246 	void *data;
247 	int rv = 0;
248 
249 	setvariable_user = (struct efi_setvariable __user *)arg;
250 
251 	if (copy_from_user(&setvariable, setvariable_user, sizeof(setvariable)))
252 		return -EFAULT;
253 	if (copy_from_user(&vendor_guid, setvariable.vendor_guid,
254 				sizeof(vendor_guid)))
255 		return -EFAULT;
256 
257 	if (setvariable.variable_name) {
258 		rv = copy_ucs2_from_user(&name, setvariable.variable_name);
259 		if (rv)
260 			return rv;
261 	}
262 
263 	data = memdup_user(setvariable.data, setvariable.data_size);
264 	if (IS_ERR(data)) {
265 		kfree(name);
266 		return PTR_ERR(data);
267 	}
268 
269 	status = efi.set_variable(name, &vendor_guid,
270 				setvariable.attributes,
271 				setvariable.data_size, data);
272 
273 	if (put_user(status, setvariable.status)) {
274 		rv = -EFAULT;
275 		goto out;
276 	}
277 
278 	rv = status == EFI_SUCCESS ? 0 : -EINVAL;
279 
280 out:
281 	kfree(data);
282 	kfree(name);
283 
284 	return rv;
285 }
286 
287 static long efi_runtime_get_time(unsigned long arg)
288 {
289 	struct efi_gettime __user *gettime_user;
290 	struct efi_gettime  gettime;
291 	efi_status_t status;
292 	efi_time_cap_t cap;
293 	efi_time_t efi_time;
294 
295 	gettime_user = (struct efi_gettime __user *)arg;
296 	if (copy_from_user(&gettime, gettime_user, sizeof(gettime)))
297 		return -EFAULT;
298 
299 	status = efi.get_time(gettime.time ? &efi_time : NULL,
300 			      gettime.capabilities ? &cap : NULL);
301 
302 	if (put_user(status, gettime.status))
303 		return -EFAULT;
304 
305 	if (status != EFI_SUCCESS)
306 		return -EINVAL;
307 
308 	if (gettime.capabilities) {
309 		efi_time_cap_t __user *cap_local;
310 
311 		cap_local = (efi_time_cap_t *)gettime.capabilities;
312 		if (put_user(cap.resolution, &(cap_local->resolution)) ||
313 			put_user(cap.accuracy, &(cap_local->accuracy)) ||
314 			put_user(cap.sets_to_zero, &(cap_local->sets_to_zero)))
315 			return -EFAULT;
316 	}
317 	if (gettime.time) {
318 		if (copy_to_user(gettime.time, &efi_time, sizeof(efi_time_t)))
319 			return -EFAULT;
320 	}
321 
322 	return 0;
323 }
324 
325 static long efi_runtime_set_time(unsigned long arg)
326 {
327 	struct efi_settime __user *settime_user;
328 	struct efi_settime settime;
329 	efi_status_t status;
330 	efi_time_t efi_time;
331 
332 	settime_user = (struct efi_settime __user *)arg;
333 	if (copy_from_user(&settime, settime_user, sizeof(settime)))
334 		return -EFAULT;
335 	if (copy_from_user(&efi_time, settime.time,
336 					sizeof(efi_time_t)))
337 		return -EFAULT;
338 	status = efi.set_time(&efi_time);
339 
340 	if (put_user(status, settime.status))
341 		return -EFAULT;
342 
343 	return status == EFI_SUCCESS ? 0 : -EINVAL;
344 }
345 
346 static long efi_runtime_get_waketime(unsigned long arg)
347 {
348 	struct efi_getwakeuptime __user *getwakeuptime_user;
349 	struct efi_getwakeuptime getwakeuptime;
350 	efi_bool_t enabled, pending;
351 	efi_status_t status;
352 	efi_time_t efi_time;
353 
354 	getwakeuptime_user = (struct efi_getwakeuptime __user *)arg;
355 	if (copy_from_user(&getwakeuptime, getwakeuptime_user,
356 				sizeof(getwakeuptime)))
357 		return -EFAULT;
358 
359 	status = efi.get_wakeup_time(
360 		getwakeuptime.enabled ? (efi_bool_t *)&enabled : NULL,
361 		getwakeuptime.pending ? (efi_bool_t *)&pending : NULL,
362 		getwakeuptime.time ? &efi_time : NULL);
363 
364 	if (put_user(status, getwakeuptime.status))
365 		return -EFAULT;
366 
367 	if (status != EFI_SUCCESS)
368 		return -EINVAL;
369 
370 	if (getwakeuptime.enabled && put_user(enabled,
371 						getwakeuptime.enabled))
372 		return -EFAULT;
373 
374 	if (getwakeuptime.time) {
375 		if (copy_to_user(getwakeuptime.time, &efi_time,
376 				sizeof(efi_time_t)))
377 			return -EFAULT;
378 	}
379 
380 	return 0;
381 }
382 
383 static long efi_runtime_set_waketime(unsigned long arg)
384 {
385 	struct efi_setwakeuptime __user *setwakeuptime_user;
386 	struct efi_setwakeuptime setwakeuptime;
387 	efi_bool_t enabled;
388 	efi_status_t status;
389 	efi_time_t efi_time;
390 
391 	setwakeuptime_user = (struct efi_setwakeuptime __user *)arg;
392 
393 	if (copy_from_user(&setwakeuptime, setwakeuptime_user,
394 				sizeof(setwakeuptime)))
395 		return -EFAULT;
396 
397 	enabled = setwakeuptime.enabled;
398 	if (setwakeuptime.time) {
399 		if (copy_from_user(&efi_time, setwakeuptime.time,
400 					sizeof(efi_time_t)))
401 			return -EFAULT;
402 
403 		status = efi.set_wakeup_time(enabled, &efi_time);
404 	} else
405 		status = efi.set_wakeup_time(enabled, NULL);
406 
407 	if (put_user(status, setwakeuptime.status))
408 		return -EFAULT;
409 
410 	return status == EFI_SUCCESS ? 0 : -EINVAL;
411 }
412 
413 static long efi_runtime_get_nextvariablename(unsigned long arg)
414 {
415 	struct efi_getnextvariablename __user *getnextvariablename_user;
416 	struct efi_getnextvariablename getnextvariablename;
417 	unsigned long name_size, prev_name_size = 0, *ns = NULL;
418 	efi_status_t status;
419 	efi_guid_t *vd = NULL;
420 	efi_guid_t vendor_guid;
421 	efi_char16_t *name = NULL;
422 	int rv = 0;
423 
424 	getnextvariablename_user = (struct efi_getnextvariablename __user *)arg;
425 
426 	if (copy_from_user(&getnextvariablename, getnextvariablename_user,
427 			   sizeof(getnextvariablename)))
428 		return -EFAULT;
429 
430 	if (getnextvariablename.variable_name_size) {
431 		if (get_user(name_size, getnextvariablename.variable_name_size))
432 			return -EFAULT;
433 		ns = &name_size;
434 		prev_name_size = name_size;
435 	}
436 
437 	if (getnextvariablename.vendor_guid) {
438 		if (copy_from_user(&vendor_guid,
439 				getnextvariablename.vendor_guid,
440 				sizeof(vendor_guid)))
441 			return -EFAULT;
442 		vd = &vendor_guid;
443 	}
444 
445 	if (getnextvariablename.variable_name) {
446 		size_t name_string_size = 0;
447 
448 		rv = get_ucs2_strsize_from_user(
449 				getnextvariablename.variable_name,
450 				&name_string_size);
451 		if (rv)
452 			return rv;
453 		/*
454 		 * The name_size may be smaller than the real buffer size where
455 		 * variable name located in some use cases. The most typical
456 		 * case is passing a 0 to get the required buffer size for the
457 		 * 1st time call. So we need to copy the content from user
458 		 * space for at least the string size of variable name, or else
459 		 * the name passed to UEFI may not be terminated as we expected.
460 		 */
461 		rv = copy_ucs2_from_user_len(&name,
462 				getnextvariablename.variable_name,
463 				prev_name_size > name_string_size ?
464 				prev_name_size : name_string_size);
465 		if (rv)
466 			return rv;
467 	}
468 
469 	status = efi.get_next_variable(ns, name, vd);
470 
471 	if (put_user(status, getnextvariablename.status)) {
472 		rv = -EFAULT;
473 		goto out;
474 	}
475 
476 	if (status != EFI_SUCCESS) {
477 		if (status == EFI_BUFFER_TOO_SMALL) {
478 			if (ns && put_user(*ns,
479 				getnextvariablename.variable_name_size)) {
480 				rv = -EFAULT;
481 				goto out;
482 			}
483 		}
484 		rv = -EINVAL;
485 		goto out;
486 	}
487 
488 	if (name) {
489 		if (copy_ucs2_to_user_len(getnextvariablename.variable_name,
490 						name, prev_name_size)) {
491 			rv = -EFAULT;
492 			goto out;
493 		}
494 	}
495 
496 	if (ns) {
497 		if (put_user(*ns, getnextvariablename.variable_name_size)) {
498 			rv = -EFAULT;
499 			goto out;
500 		}
501 	}
502 
503 	if (vd) {
504 		if (copy_to_user(getnextvariablename.vendor_guid, vd,
505 							sizeof(efi_guid_t)))
506 			rv = -EFAULT;
507 	}
508 
509 out:
510 	kfree(name);
511 	return rv;
512 }
513 
514 static long efi_runtime_get_nexthighmonocount(unsigned long arg)
515 {
516 	struct efi_getnexthighmonotoniccount __user *getnexthighmonocount_user;
517 	struct efi_getnexthighmonotoniccount getnexthighmonocount;
518 	efi_status_t status;
519 	u32 count;
520 
521 	getnexthighmonocount_user = (struct
522 			efi_getnexthighmonotoniccount __user *)arg;
523 
524 	if (copy_from_user(&getnexthighmonocount,
525 			   getnexthighmonocount_user,
526 			   sizeof(getnexthighmonocount)))
527 		return -EFAULT;
528 
529 	status = efi.get_next_high_mono_count(
530 		getnexthighmonocount.high_count ? &count : NULL);
531 
532 	if (put_user(status, getnexthighmonocount.status))
533 		return -EFAULT;
534 
535 	if (status != EFI_SUCCESS)
536 		return -EINVAL;
537 
538 	if (getnexthighmonocount.high_count &&
539 	    put_user(count, getnexthighmonocount.high_count))
540 		return -EFAULT;
541 
542 	return 0;
543 }
544 
545 static long efi_runtime_query_variableinfo(unsigned long arg)
546 {
547 	struct efi_queryvariableinfo __user *queryvariableinfo_user;
548 	struct efi_queryvariableinfo queryvariableinfo;
549 	efi_status_t status;
550 	u64 max_storage, remaining, max_size;
551 
552 	queryvariableinfo_user = (struct efi_queryvariableinfo __user *)arg;
553 
554 	if (copy_from_user(&queryvariableinfo, queryvariableinfo_user,
555 			   sizeof(queryvariableinfo)))
556 		return -EFAULT;
557 
558 	status = efi.query_variable_info(queryvariableinfo.attributes,
559 					 &max_storage, &remaining, &max_size);
560 
561 	if (put_user(status, queryvariableinfo.status))
562 		return -EFAULT;
563 
564 	if (status != EFI_SUCCESS)
565 		return -EINVAL;
566 
567 	if (put_user(max_storage,
568 		     queryvariableinfo.maximum_variable_storage_size))
569 		return -EFAULT;
570 
571 	if (put_user(remaining,
572 		     queryvariableinfo.remaining_variable_storage_size))
573 		return -EFAULT;
574 
575 	if (put_user(max_size, queryvariableinfo.maximum_variable_size))
576 		return -EFAULT;
577 
578 	return 0;
579 }
580 
581 static long efi_runtime_query_capsulecaps(unsigned long arg)
582 {
583 	struct efi_querycapsulecapabilities __user *qcaps_user;
584 	struct efi_querycapsulecapabilities qcaps;
585 	efi_capsule_header_t *capsules;
586 	efi_status_t status;
587 	u64 max_size;
588 	int i, reset_type;
589 	int rv = 0;
590 
591 	qcaps_user = (struct efi_querycapsulecapabilities __user *)arg;
592 
593 	if (copy_from_user(&qcaps, qcaps_user, sizeof(qcaps)))
594 		return -EFAULT;
595 
596 	if (qcaps.capsule_count == ULONG_MAX)
597 		return -EINVAL;
598 
599 	capsules = kcalloc(qcaps.capsule_count + 1,
600 			   sizeof(efi_capsule_header_t), GFP_KERNEL);
601 	if (!capsules)
602 		return -ENOMEM;
603 
604 	for (i = 0; i < qcaps.capsule_count; i++) {
605 		efi_capsule_header_t *c;
606 		/*
607 		 * We cannot dereference qcaps.capsule_header_array directly to
608 		 * obtain the address of the capsule as it resides in the
609 		 * user space
610 		 */
611 		if (get_user(c, qcaps.capsule_header_array + i)) {
612 			rv = -EFAULT;
613 			goto out;
614 		}
615 		if (copy_from_user(&capsules[i], c,
616 				sizeof(efi_capsule_header_t))) {
617 			rv = -EFAULT;
618 			goto out;
619 		}
620 	}
621 
622 	qcaps.capsule_header_array = &capsules;
623 
624 	status = efi.query_capsule_caps((efi_capsule_header_t **)
625 					qcaps.capsule_header_array,
626 					qcaps.capsule_count,
627 					&max_size, &reset_type);
628 
629 	if (put_user(status, qcaps.status)) {
630 		rv = -EFAULT;
631 		goto out;
632 	}
633 
634 	if (status != EFI_SUCCESS) {
635 		rv = -EINVAL;
636 		goto out;
637 	}
638 
639 	if (put_user(max_size, qcaps.maximum_capsule_size)) {
640 		rv = -EFAULT;
641 		goto out;
642 	}
643 
644 	if (put_user(reset_type, qcaps.reset_type))
645 		rv = -EFAULT;
646 
647 out:
648 	kfree(capsules);
649 	return rv;
650 }
651 
652 static long efi_test_ioctl(struct file *file, unsigned int cmd,
653 							unsigned long arg)
654 {
655 	switch (cmd) {
656 	case EFI_RUNTIME_GET_VARIABLE:
657 		return efi_runtime_get_variable(arg);
658 
659 	case EFI_RUNTIME_SET_VARIABLE:
660 		return efi_runtime_set_variable(arg);
661 
662 	case EFI_RUNTIME_GET_TIME:
663 		return efi_runtime_get_time(arg);
664 
665 	case EFI_RUNTIME_SET_TIME:
666 		return efi_runtime_set_time(arg);
667 
668 	case EFI_RUNTIME_GET_WAKETIME:
669 		return efi_runtime_get_waketime(arg);
670 
671 	case EFI_RUNTIME_SET_WAKETIME:
672 		return efi_runtime_set_waketime(arg);
673 
674 	case EFI_RUNTIME_GET_NEXTVARIABLENAME:
675 		return efi_runtime_get_nextvariablename(arg);
676 
677 	case EFI_RUNTIME_GET_NEXTHIGHMONOTONICCOUNT:
678 		return efi_runtime_get_nexthighmonocount(arg);
679 
680 	case EFI_RUNTIME_QUERY_VARIABLEINFO:
681 		return efi_runtime_query_variableinfo(arg);
682 
683 	case EFI_RUNTIME_QUERY_CAPSULECAPABILITIES:
684 		return efi_runtime_query_capsulecaps(arg);
685 	}
686 
687 	return -ENOTTY;
688 }
689 
690 static int efi_test_open(struct inode *inode, struct file *file)
691 {
692 	/*
693 	 * nothing special to do here
694 	 * We do accept multiple open files at the same time as we
695 	 * synchronize on the per call operation.
696 	 */
697 	return 0;
698 }
699 
700 static int efi_test_close(struct inode *inode, struct file *file)
701 {
702 	return 0;
703 }
704 
705 /*
706  *	The various file operations we support.
707  */
708 static const struct file_operations efi_test_fops = {
709 	.owner		= THIS_MODULE,
710 	.unlocked_ioctl	= efi_test_ioctl,
711 	.open		= efi_test_open,
712 	.release	= efi_test_close,
713 	.llseek		= no_llseek,
714 };
715 
716 static struct miscdevice efi_test_dev = {
717 	MISC_DYNAMIC_MINOR,
718 	"efi_test",
719 	&efi_test_fops
720 };
721 
722 static int __init efi_test_init(void)
723 {
724 	int ret;
725 
726 	ret = misc_register(&efi_test_dev);
727 	if (ret) {
728 		pr_err("efi_test: can't misc_register on minor=%d\n",
729 			MISC_DYNAMIC_MINOR);
730 		return ret;
731 	}
732 
733 	return 0;
734 }
735 
736 static void __exit efi_test_exit(void)
737 {
738 	misc_deregister(&efi_test_dev);
739 }
740 
741 module_init(efi_test_init);
742 module_exit(efi_test_exit);
743